Endogenetic forces
Reliefs created on earth surface due to vertical irregularities
Example plateau, mountain, plane, lakes, faults, folds etc.
Isostasy - balance between the outstanding and low lying parts of the earth
Based on intensity
Diastrophic forces
Sudden forces
vertical or epeirogenic movements( continent making movements)
Horizontal or orogenic movements ( mountain building movements)
Upward movement
Downward movement
Cause emergence of continents
Cause emergence of coastal areas
Cause subsistence or submergence
Ex. submerged forest in Prince dock area of Mumbai
Compressional forces
Tensional forces
The Rock Strata get folded
Upfolded rock beds are called anticlines
Down folded Rock Strata are cold synclines
Different types of foldings
Symmetrical folds examples Jura mountains of Switzerland
Asymmetrical folds example Southern pennine mountains of Britain
Monoclinal folds example great dividing range of Australia
Over fold example Pir Panjal range in India
Isoclinal fold example kala Chitta mountains in Pakistan
Recumbent fold example carrick Castle mountains of Britain
Overthrust fold example Pir Panjal range in Kashmir and Garhwal Himalayas
Nappe -When Limbs of recumbent fold breaks and moves some distance overriding rock beds Example Kashmir Valley
Faults -Cracks fractures and faulting are included in it
Fanfold -Represent an extensive and broad fold consisting of several minor anticlines and synclines called anticlinorium and synclinorium
Formed due to combined effort of both the compressional and tensional forces but the tensional force is play significant role
Normal fault - formed due to stress, in this Rock blocks are displaced in opposite directions and one of the blocks moves downward
Surface get stretched
Reverse faults - formed due to compressional forces, in this Rock blocks move towards each other and one rock block overrides the other
The folded area gets compressed also called thrust fault
Step faults - a series of faults occur in any area in such a way that the slopes of all the fold planes of all the faults are in same direction
Example Rhine valley in Europe
Strike- slip or transcurrent faults - when rocks are compressed from two opposite direction The Rock blocks move forward or backward instead of upward and downward
Example San Andreas fault in California
Folding results into
Rift Valley - represents a trough, depression or basin between two crustal parts.
formed due to subsidence of middle portion between two normal faults
Formed due to movement of Rock blocks in two opposite directions( upward or downward) due to tensional forces
They are long and narrow called grabbin in German, Dead Sea of Jordan located in rift Valley
Ramp Valleys - formed when the middle portion between two fold planes remain at its place but due to compressional forces the two side Rock blocks rise upwards example Brahmaputra Valley
Block mountains - when middle portion remains at its place and the two side blocks move downwards example Satpura mountains in India black forest and vosges in Germany
Horst mountains - when two side block of a fault remain at their places but the middle block Rises along the fault